Twisted pair cable feeding mechanism and method

ABSTRACT

A mechanism ( 10 ) for feeding a length of twisted pair cable ( 15 ), comprises a driven capstan ( 11 ) and a continuous belt ( 17 ) defining, respectively, first and second contact surfaces for the twisted pair cable ( 15 ). The continuous belt ( 17 ) is supported and arranged so that a portion thereof embraces an arc ( 16 ) of the substantially circular periphery of the capstan ( 11 ). Drive means are provided to effect rotation of the capstan ( 11 ), so as to feed a length of twisted pair cable ( 15 ) along the arcuate path ( 16 ) defined between the first and second contact surfaces where the arc ( 16 ) of the capstan ( 11 ) intersects the continuous belt ( 17 ). The arcuate path ( 16 ) is sufficiently narrow such that the capstan ( 11 ) and the continuous belt ( 17 ) embrace the length of twisted pair cable ( 15 ), and sufficiently long such that at least two nodes ( 19 ) of said length of twisted pair cable ( 15 ) are accommodated therein. This arrangement ensures feeding of the twisted pair cable ( 15 ) along the arcuate path ( 16 ) without causing rotation of the cable ( 15 ) about its axis.

This invention relates to a mechanism and method for feeding a length of twisted pair cable. In particular, the invention relates to such a mechanism and method for use in an automated or robotic wiring system.

Twisted pair cabling is commonly used in telecommunications networks, and comprises two individual insulated wire conductors wound together in a regular helical configuration, to reduce interference and increase strength. The wiring of telecommunications network distribution frames using twisted pair cable has conventionally been performed by hand, or using simple hand-operated tools. However, a typical distribution frame may comprise many thousands of individual connections, requiring constant maintenance and re-wiring. Performing such operations by hand is therefore slow, labour intensive and susceptible to error. Consequently, the introduction of automated wiring systems is therefore highly desirable.

Automated apparatus and methods for wiring the insulated wire conductors of a length of twisted pair cable into an insulation displacement connector block of a telecommunications network distribution frame are described in the applicant's International Patent Applications Nos. PCT/GB2008/050079 and PCT/GB2008/050136. The twisted pair cable feeding mechanism and method of the present invention is intended for use in combination with those apparatus and methods, to deliver a length of twisted pair cable to the wiring head of an automated or robotic wiring system.

Various mechanisms have been disclosed for the feeding of cables, ropes, tapes and the like. A common arrangement involves the use of a pair of pinch rollers, between which the cable is guided, with one or both rollers being driven, so as to cause displacement of the cable. Though such arrangements work well for the feeding of many types of cables, ropes, tapes and the like, they are not suitable for use with twisted pair cabling. Because of the helical configuration of twisted pair cabling, the pinching of the cable by the rollers whilst the rollers are simultaneously driving the cable therethrough, tends to cause rotation of the cable about its axis during feeding. This is undesirable as it can lead to excessive, uncontrolled and irregular twisting of the cable.

The present invention seeks to provide a mechanism and method for feeding a length of twisted pair cable which eliminates or minimises rotation of the twisted pair cable about its axis, during feeding.

According to a first aspect of the present invention, there is provided a mechanism for feeding a length of twisted pair cable, comprising:

a first contact surface;

a second opposed contact surface;

a path adapted to receive a length of twisted pair cable, said path being defined between said first and second contact surfaces; and

drive means adapted to effect motion of at least one of said first and second contact surfaces, thereby to drive a length of twisted pair cable along said path;

and wherein said path is sufficiently narrow such that said first and second contact surfaces embrace a length of twisted pair cable inserted into the path, and sufficiently long such that at least two nodes of said length of twisted pair cable are accommodated therein, such that in use, said twisted pair cable is driven along the path, without causing rotation of said twisted pair cable about its axis.

According to a principal embodiment of the first aspect of the present invention, there is provided a mechanism for feeding a length of twisted pair cable, comprising:

a capstan having a substantially circular periphery;

a continuous belt supported so that a portion thereof embraces an arc of the capstan periphery; and

drive means for effecting rotation of the capstan;

whereby rotation of the capstan effects feeding of a length of twisted pair cable around said arc of the capstan periphery, without causing rotation of the cable about it axis.

In this principal embodiment, the first contact surface comprises a capstan having a substantially circular periphery; the second opposed contact surface comprises a portion of a continuous belt supported such that said portion embraces an arc of the capstan periphery; and the drive means is adapted to effect rotation of the capstan, thereby to effect feeding of a length of twisted pair cable around said arc of the capstan periphery, without causing rotation of the twisted pair cable about its axis.

Consequently, the path along which the twisted pair cable is fed by the mechanism of the first aspect of the present invention is at least partially defined by the arc of the capstan periphery. Preferably, the path comprises an arc of substantially 90°.

The continuous belt is preferably supported on at least two, and more preferably three, rollers. The rollers are preferably arranged such that the axes thereof are parallel to one another and to the axis of the capstan.

Where the continuous belt is supported on three rollers, these are preferably arranged relative to one another so as to form the corners of a triangle, and arranged relative to the capstan such that an arc of the capstan periphery intersects one side of said triangle. Most preferably, the three rollers are arranged relative to one another so as to form the corners of a right-angled triangle, and arranged relative to the capstan such that an arc of the capstan periphery intersects the hypotenuse of said right-angled triangle. It should be understood however that whilst these arrangements of the rollers and belt are preferred, many other arrangements may nevertheless also be employed.

At least one roller preferably comprises a cylindrical body adapted to receive the continuous belt, and upper and lower flanges extending radially beyond the cylindrical body so as to constrain the belt therebetween. Preferably the upper and lower flanges extend radially beyond the cylindrical body a distance at least as large as the thickness of the continuous belt. Alternatively, an annular groove may be formed in the cylindrical body of the roller, for receiving the continuous belt therein.

The capstan preferably also comprises a cylindrical body, defining the first contact surface for a length of twisted pair cable, said cable also being embraced by the second opposed contact surface defined by the continuous belt. The capstan may desirably also be provided with upper and lower flanges extending radially beyond the cylindrical body so as to constrain the cable and belt therebetween. The twisted pair cable feeding mechanism according to the first aspect of the present invention preferably further, comprises guide means adapted to direct the twisted pair cable around an arc of the capstan periphery. Most preferably, the mechanism comprises first and second guide means adapted, respectively, to direct the twisted pair cable towards, and away from, the capstan periphery. The first and second guide means therefore further define the path along which the twisted pair cable is fed. Where, as in preferred embodiments of the present invention, the path comprises an arc of substantially 90°, the first and second guide means are thus preferably arranged at substantially 90° to one another.

Each guide means may preferably comprise a block having a channel formed therein, adapted to receive passage of a length of twisted pair cable therethrough. Where the path comprises an arc of substantially 90°, the axes of the channels of the first and second guide means will necessarily also be arranged at substantially 90° to one another.

The drive means preferably comprises an electric motor coupled to the capstan to effect rotational movement thereof. The drive means, or further drive means, may be adapted also to effect rotational movement of the rollers. Alternatively, the rollers may be adapted to rotate freely upon rotation of the capstan.

The mechanism preferably further comprises means for adjusting the tension of the continuous belt. This may be achieved, for example, by mounting at least one of the rollers such that the axis thereof is adapted for translational motion relative to the axes of the other rollers, and/or the capstan. Alternatively, or additionally, the capstan may be mounted on a first platform, and the rollers mounted on a second platform; with at least one of said first and second platforms being adapted for translational motion relative to the other.

The mechanism of the first aspect of the present invention is preferably adapted for feeding a length of twisted pair cable to a wiring head of an automated or robotic wiring system.

According to a second aspect of the present invention there is provided a method of feeding a length of twisted pair cable, said method comprising the steps of:

introducing a length of twisted pair cable into a path defined between a first contact surface, and a second opposed contact surface, said path being sufficiently narrow such that said first and second contact surfaces embrace said length of twisted pair cable, and sufficiently long such that at least two nodes of said length of twisted pair cable are accommodated therein; and

driving at least one of said first and second opposed contact surfaces, so as to effect feeding of the twisted pair cable along the path, without causing rotation of said twisted pair cable about its axis.

According to a principal embodiment of the second aspect of the present invention, there is provided a method of feeding a length of twisted pair cable, said method comprising the steps of:

introducing a length of twisted pair cable between a first contact surface defined by a substantially circular periphery of a driven capstan, and a second opposed contact surface defined by a continuous belt supported so that a portion thereof embraces an arc of the capstan periphery, said first and second opposed contact surfaces being adapted to receive and embrace said length of twisted pair cable therebetween; and

driving the capstan so as to effect feeding of the twisted pair cable through a path at least partially defined by said arc of the capstan periphery.

In this principal embodiment, the first contact surface comprises a capstan having a substantially circular periphery, the second opposed contact surface comprises a portion of a continuous belt supported such that said portion embraces an arc of the capstan periphery; and the capstan is driven to effect feeding of a length of twisted pair cable along a path at least partially defined by said arc of the capstan periphery, thereby effecting feeding of the twisted pair cable without causing rotation of said twisted pair cable about its axis.

The path at least partially defined by said arc of the capstan periphery preferably comprises an arc of substantially 90°. The method according to the second aspect of the present invention thus effects feeding of a length of twisted pair cable through a 90° turn.

The method according to the second aspect of the present invention preferably effects the feeding of a length of twisted pair cable to a wiring head of an automated or robotic wiring system.

The scope of the present invention encompasses a method of feeding a length of twisted pair cable as hereinbefore described utilising a twisted pair cable feeding mechanism as hereinbefore described. In order that the present invention may be fully understood, a preferred embodiment thereof will now be described in detail, though only by way of example, with reference to the accompanying drawing, in which:

FIG. 1 shows a perspective view of a twisted pair cable feeding mechanism according to a preferred embodiment of the first aspect of the present invention.

Referring now to FIG. 1, there is shown a twisted pair cable feeding mechanism, generally indicated 10, according to a first aspect of the present invention. The mechanism 10 comprises a capstan 11 having a cylindrical body 12 presenting a circular periphery, and first and second guide means 13,14 respectively, arranged to direct a length of twisted pair cable 15 around an arc 16 of the capstan periphery.

A continuous belt 17 is supported on three rollers 18 arranged so as to define the corners of a notional right-angled triangle. The continuous belt 17 would define all three sides of said notional right-angled triangle defined by the three rollers 18, if the roller 18 and belt 17 ensemble were in isolation. However, when assembled in the mechanism 10 of the present invention, the rollers 18 are arranged in close proximity to the capstan 11, such that said arc 16 of the capstan periphery intersects the hypotenuse of said notional right-angled triangle. The continuous belt 17 is thus diverted from its linear path, along the arc 16 of the capstan periphery.

An arcuate path 16 for the length of twisted pair cable 15 is thus defined between a first contact surface formed by the cylindrical body 12 of the capstan 11 and a second opposed contact surface formed by the belt 17 (the first and second contact surfaces are not visible in FIG. 1).

The spacing between the first and second contact surfaces must be sufficiently small such that the length of twisted pair cable 15 is gripped between the said contact surfaces, so as to be urged along the arcuate path 16 upon rotation of the capstan 11. Additionally, the length of the arcuate path 16 must be sufficiently long such that at least two nodes 19 of the twisted pair cable 15 are accommodated therein, so that no net force acts to rotate the cable 15 about its axis, but only to urge the cable 15 along the arcuate path 16.

The cylindrical body 12 of the capstan 11 is provided with upper and lower flanges 21 having a diameter greater than that of the cylindrical body 12 so as to constrain the twisted pair cable 15 and the belt 17 therebetween, along the arcuate path 16. A similar construction is adopted for the rollers 18, each of which comprises a cylindrical body 22, which may be provided with upper and lower flanges 23 extending radially beyond the cylindrical body 22 so as to constrain the belt 17 therebetween.

As can be appreciated from FIG. 1, the capstan 11 is rotatable about a central axle 24, whilst each roller 18 is also rotatable about a central axle 25, each said axle 24, 25 extending parallel to one another. An electric motor (not shown) is coupled to the capstan axle 24 so as to drive rotation of the capstan 11. The axles 25 of the rollers 18 are adapted to rotate freely in response to the motion of the belt 17 caused by rotation of the capstan 11. It should be understood however, that in alternative preferred embodiments of the mechanism 10 of the present invention, drive means may also be coupled to the roller axles 25 so as to drive rotation of the rollers 18.

The first and second guide means 13, 14 are arranged to direct the twisted pair cable 15 around the arc 16 of the capstan 11. Each said guide means 13, 14 comprises a block 26 having a channel 27 formed therein. Each channel 27 is sized to allow the length of twisted pair cable 15 to be passed therethrough upon operation of the mechanism 10. The channels 27 of the respective guide means 13, 14 are arranged at 90° to one another in order to facilitate passage of the length of twisted pair cable 15 along the arcuate 90° path 16.

In performing a method of feeding a length of twisted pair cable, according to a second aspect of the present invention, the length of twisted pair cable 15 must be introduced through the first guide means 13, and into the arcuate path 16 defined between the first contact surface formed by the cylindrical body 12 of the capstan 11 and the second opposed contact surface formed by the belt 17. Rotation of the capstan 11 by operation of the electric motor (not shown) then urges the cable 15 through the remainder of the arcuate path 16, from where the cable 15 can be threaded through the second guide means 14. On emerging from the second guide means 14 the cable 15 is then fed to a wiring head (not shown) of a robotic wiring system. In use, to move the twisted pair cable 15 in the direction of arrow a the capstan 11 should be driven to rotate in a clockwise motion, whilst to move the twist pair cable 15 in the direction of arrow b, the capstan 11 should be driven to rotate in a counter-clockwise motion. 

1. A mechanism for feeding a length of twisted pair cable, said mechanism comprising: a first contact surface; a second opposed contact surface; a path defined between said first and second contact surfaces and adapted to receive a length of twisted pair cable; and drive means adapted to effect motion of at least one of said first and second contact surfaces, thereby to drive a length of twisted pair cable along said path; whereby in use, said first and second contact surfaces embrace a length of twisted pair cable inserted into the path, such that at least two nodes of said length of twisted pair cable are accommodated therein, and said twisted pair cable is driven along the path, without causing rotation of said twisted pair cable about its axis.
 2. (canceled)
 3. The mechanism of claim 1, in which: the first contact surface comprises a capstan having a substantially circular periphery; the second opposed contact surface comprises a portion of a continuous belt supported such that said portion embraces an arc of the capstan periphery; and the drive means is adapted to effect rotation of the capstan; whereby in use, rotation of the capstan effects feeding of a length of twisted pair cable around said arc of the capstan periphery, without causing rotation of said length of twisted pair cable about its axis.
 4. The mechanism of claim 2, in which a path adapted to receive a length of twisted pair cable is at least partially defined by said arc of the capstan periphery, said arc comprising an arc of substantially 90°.
 5. (canceled)
 6. The mechanism of claim 2, in which said continuous belt is supported on at least two rollers.
 7. The mechanism of claim 6, in which the continuous belt is supported on three rollers.
 8. The mechanism of claim 6, in which said rollers and said capstan are arranged such that axes thereof are parallel to one another.
 9. The mechanism of claim 7, in which said three rollers are arranged so as to form corners of a triangle, and wherein an arc of the capstan periphery intersects one side of said triangle.
 10. The mechanism of claim 9, in which said three rollers are arranged so as to form corners of a right-angled triangle having a hypotenuse, and wherein an arc of the capstan periphery intersects said hypotenuse of said right-angled triangle.
 11. The mechanism of claim 6, in which at least one roller comprises a cylindrical body adapted to receive the continuous belt, and upper and lower flanges extending radially beyond said cylindrical body so as to constrain the belt therebetween.
 12. The mechanism of claim 3, in which the capstan comprises a cylindrical body defining said first contact surface for a length of twisted pair cable also being embraced by said second opposed contact surface defined by the continuous belt, and upper and lower flanges extending radially beyond said cylindrical body so as to constrain said cable and belt therebetween.
 13. The mechanism of claim 3, further comprising guide means adapted to direct said twisted pair cable around an arc of the capstan periphery.
 14. (canceled)
 15. (canceled)
 16. The mechanism of claim 13, comprising first and second guide means further defining said path adapted to receive a length of twisted pair cable, said first and second guide means being arranged at substantially 90° to one another.
 17. The mechanism of claim 16, in which each guide means comprises a block having a channel formed therein, said channel being adapted to receive passage of a length of twisted pair cable therethrough, and wherein axes of the channels of said first and second guide means are arranged at substantially 90° to one another.
 18. (canceled)
 19. (canceled)
 20. The mechanism of claim 6, in which the drive means is adapted also to effect rotational movement of one or more of said rollers.
 21. The mechanism of claim 6, in which said rollers are adapted to rotate freely upon rotation of the capstan.
 22. (canceled)
 23. The mechanism of claim 1, adapted for feeding a length of twisted pair cable to a wiring head of an automated or robotic wiring system.
 24. A method of feeding a length of twisted pair cable, said method comprising steps of: introducing a length of twisted pair cable into a path defined between a first contact surface, and a second opposed contact surface, such that said first and second contact surfaces embrace said length of twisted pair cable, and such that at least two nodes of said length of twisted pair cable are accommodated therein; and driving at least one of said first and second opposed contact surfaces, so as to effect feeding of said length of twisted pair cable along said path, without causing rotation of said twisted pair cable about its axis.
 25. (canceled)
 26. The method of claim 24, in which the first contact surface comprises a capstan having a substantially circular periphery, the second opposed contact surface comprises a portion of a continuous belt supported such that said portion embraces an arc of the capstan periphery; and the capstan is driven so as to effect feeding of a length of twisted pair cable along a path at least partially defined by said arc of the capstan periphery, thereby effecting feeding of said length of twisted pair cable without causing rotation of said twisted pair cable about its axis.
 27. The method of claim 26, in which said path at least partially defined by said arc of the capstan periphery comprises an arc of substantially 90°.
 28. The method of claim 24, adapted for feeding a length of twisted pair cable to a wiring head of an automated or robotic wiring system.
 29. (canceled) 